1. Field of the Invention
This invention pertains generally to electric motors and generators. More specifically, this invention pertains to permanent magnet motors wherein the rotor is formed using permanent magnets secured to a core with plastic molded over the magnets and core.
2. General Background
In permanent magnet electric motors, establishing and maintaining magnet placement and spacing during manufacturing of the rotor is important. This is particularly the case with rotors formed with magnet segments that are secured to the rotor with over molded plastic. Prior art methods of establishing and maintaining magnet placement and spacing during manufacture include, using a die device with fixtures to secure the magnets in place and using a cup design to locate and orientate the magnets. However, using a die with fixtures makes the manufacturing process much more complicated and time consuming. Still further, the use of a cup design to locate and orientate the magnets during manufacture of the rotor requires that the rotor core be in place before the magnets can be placed in their proper locations.